The present invention relates to projection screens used to display moving and still images, and, in particular, to a screen with a movable shutter.
Although projection screens have most commonly been used for movie theatres, educational and industrial image projection, and home entertainment systems, projection screens are finding many new applications related to computer-based simulators and games. These new applications include visual simulations of physical environments, such as race tracks, football fields, battlefields, and airports, in order to provide visual cues to a person interacting with various controls and instruments to control the movement and activities of one or more objects within the simulated environments, such as cars, football players, soldiers and armored equipment, and airplanes.
In certain of the above-mentioned applications, projection of a physical object through an enhanced projection screen towards a person interacting with the computer-based simulated environment can provide added realism and an essentially new dimension to the otherwise 2-dimentional nature of projected images. For example, in a simulation of a martial arts competition, an object thrown by a simulated opponent might be physically projected through the enhanced projection screen from a position on the surface of the enhanced projection screen that coincides with the projected image of the simulated opponent""s throwing hand at the point in time that the simulated opponent releases the object. As another example, a simulator used by baseball players for batting practice may project a baseball through a projection screen displaying the image of a baseball pitcher pitching a baseball. Currently-available simulators that involve projection of physical objects from projection screens include one or several fixed locations, or ports, on the projection screen from which physical objects can be projected, greatly limiting the types of actions, such as throwing a martial arts weapon or a baseball, that can be simulated. In addition, the simulated images of the throwers must be unnaturally fitted and positioned so that the release point of a thrown object in the projected image physically coincides with a fixed port on the projection screen.
Alternatively, in certain applications, it may be desirable to use a projection screen that can accept objects. A projection screen may be used as a sorter, for example, behind which bins are placed for the collection of objects that are passed through the screen to fall into different bins. A projection screen that can accept objects is also desirable for entertainment applications. In a football system, for example, users may throw footballs at the projection screen. A passer throwing a football at a virtual receiver displayed on the projection screen can either throw an accurate pass that goes through an opening on the projection screen, or can throw an errant pass that hits the projection screen and bounces away from the projection screen. All such applications are constrained by the fixed position of the openings in currently-available projection screens.
Vendors of simulation and gaming systems have thus recognized a need for a projection screen through which physical objects may be passed at essentially any position on the screen via a movable port. Additionally, vendors of simulation and gaming systems have recognized a need for the ability to synchronize opening of the movable port in time and position with images displayed on the projection screen.
One embodiment of the present invention is a projection screen having a movable shutter that can be arbitrarily positioned within an inner rectangular region of the surface of the projection screen. When the movable shutter is closed, the projection screen appears, from a distance, to be a continuous, uniformly reflective, opaque surface. The movable shutter can be opened for predetermined lengths of time to allow objects, light signals, or other entities that cannot pass through a reflective screen to pass through the opened movable shutter.
The projection screen with movable shutter comprises a main frame having a front frame to which 5 separate reflective screens are mounted, a horizontally translatable frame mounted within the main frame, and a vertically translatable shutter assembly mounted within the horizontally translatable frame. The horizontally translatable frame can move across the interior-side of the front frame, under control of an electrical motor, to position the vertically translatable shutter assembly with respect to a horizontal axis defining locations on the projection screen. The vertically translatable shutter assembly moves up and down within the horizontally translatable frame, under control of an electrical motor, to position the vertically translatable shutter assembly with respect to a vertical axis defining locations on the projection screen. Thus, the vertical shutter assembly can be positioned at any location within a large rectangular area of the projection screen, defined by a pair of Cartesian coordinates x, z, by horizontal translation of the horizontally translatable frame to an x coordinate and vertical translation of the vertically translatable shutter assembly to a z coordinate.
The reflective surface of the projection screen comprises five flexible sheets. A first flexible sheet is attached to the left side of the horizontally translatable frame and is taken up and extended by a vertically-mounted, spring-loaded take-up/supply reel mounted on the left side of the front frame. Similarly, a second flexible reflective sheet is attached to the right side of the horizontally translatable frame and is taken up and extended by a vertically mounted, spring-loaded take-up/supply reel on the right side of the front frame. A third reflective, flexible sheet with a slot, or aperture, is held between lower and upper electrical-motor-operated take-up/supply reels that are horizontally-mounted to the bottom and top of the horizontally translatable frame. The vertically translatable shutter assembly has a front frame to which a face-plate with an aperture is mounted. The forward-facing surface of the face-plate has the same reflectivity and color as the five reflective, flexible sheets. Fourth and fifth reflective, flexible sheets are mounted vertically behind the third reflective, flexible sheet via spring-loaded, take-up/supply reels horizontally mounted to the top and bottom of the front frame of the vertically translatable shutter assembly so that the fourth and fifth reflective, flexible sheets extend vertically above the vertically translatable shutter assembly to the top of the main frame and below the vertically translatable shutter assembly to the bottom of the main frame. The five reflective, flexible sheets present to a viewer of the projection screen the appearance of a continuous, flat, unbroken reflective display surface except when the aperture in the third, reflective, flexible sheet is moved past the aperture in the face plate mounted to the vertically translatable shutter assembly. While the two apertures overlap, an opening appears in the surface of the projection screen directly in front of the vertically translatable shutter assembly. The speed of movement of the third, reflective, flexible sheet determines the period of time during which the movable shutter is open. Movement of the horizontally translatable frame, the vertically translatable shutter assembly, and the third reflective, flexible screen is controlled by electrical servo motors that are, in turn, controlled by signals generated by a software program running on a computer.